Mounties in Kelowna say they've uncovered a sophisticated drug-trafficking ring that depended on the dark web and Bitcoin to sell fentanyl and carfentanil around the world.

Two residents of the Okanagan city — a 35-year-old man and a 28-year-old woman — have both been arrested after a year-long investigation into the operation, according to RCMP.

"It has been indicated this may be one of the most significant and perhaps the most sophisticated fentanyl/carfentanil trafficking and exportation enterprises that has been uncovered in Canada to date," RCMP Sgt. Alex Lynch said in a statement.

Kelowna RCMP display evidence seized during an investigation into an alleged fentanyl and carfentanil-trafficking ring. (RCMP)

Kelowna RCMP worked with authorities from across Canada, the U.S. and Australia on the investigation, dubbed "Project E-Neophile." The probe culminated with searches at a business in the 1500 block of Pandosy Street and a home in the 1100 block of Loseth Drive.

"As many as 25 packages suspected of containing fentanyl or carfentanil, destined for Canadian, American, European and Australian cities, were intercepted by authorities," said RCMP Cpl. Jesse O'Donaghey.

The packages were being sent via express courier

Police also seized two guns, $68,000 US in the digital currency, Bitcoin, 120 grams of suspected fentanyl and carfentanil and more than three kilograms of unknown substances.

Drugs on the dark web

The investigation began in September 2016, focussing on two Kelowna residents suspected of importing fentanyl and carfentanil in bulk from overseas, according to RCMP.

Police allege the suspects were using the dark web — sites that aren't accessible by common search engines — to traffic in the deadly drugs, mailing packages to destinations across North America.

The user profile connected to the suspects disappeared in November 2016, but a new profile popped up in July on a different dark web marketplace, allowing officers to obtain enough evidence for search warrants.

Both suspects face potential charges in connection with the investigation. They have been released from custody and are scheduled to appear in court Dec. 8.

Mounties say some of the information gathered during the probe has been shared with U.S. Homeland Security, allowing officers south of the border to make drug seizures in five other investigations.